4.6. Phage Stability under Different Conditions

The ability of phages to survive in different environmental conditions was assessed (i) by incubation of the phage sample (10⁶ PFU/mL in SM buffer) at 4, 10, 20, 30, 40, 50, 60 and 70 °C for one h in a ThermoMixer F 2.0 (Eppendorf, Hamburg, Germany); (ii) by the addition of a range of buffer solutions (20 mM Tris-HCl/20 mM Na citrate/20 mM Na phosphate), adjusted with NaOH to a pH in the range 2–12 to a 10⁷ PFU/mL phage, with further incubation at 25 °C for one h; (iii) by the exposure of a phage sample (10⁶ PFU/mL in SM buffer) to UV-B (280–315 nm) radiation using a PL-S9W/12/2p lamp (Philips, Amsterdam, The Netherlands) according to [42]. Treated phages were titrated on YD agar/CFBP 2214 using the plaque assay method. Procedures were carried out in triplicate and the results were averaged.